1. Technical Field
The disclosure relates to a filter, and more particularly to a charge domain filter (CDF).
2. Related Art
A conventional switch-capacitor network (SCN) is a common circuit in discrete time signal processing, which includes a plurality of switches and a plurality of capacitors. The SCN is commonly seen in the filter technology. Compared with the capacitor-resistor analog filter circuit, a filtering effect of the SCN mainly depends on size ratios among the capacitors. Even though the areas of the capacitors are changed because of the variations of the process, as the size ratios of the capacitors do not change with the variations of the process, the filtering effect of the SCN is still not changed. Therefore, the SCN is very suitable for being fabricated in a chip. However, a bandwidth compensation circuit is not used in most of the conventional CDFs, so the bandwidth is relatively narrow.